What happened
On 08 January 2024, at 11:33 UTC, a loss of separation occurred within the Barcelona CTR (control zone) involving two commercial aircraft. The first aircraft, an Airbus A-319-132, registration D-AGWD, operated by Eurowings, was arriving from Hamburg. The second aircraft, a Boeing 777-21HLR, registration A6-EWE, operated by Emirates, was arriving from Mexico City.
Both aircraft were on approach to Barcelona-El Prat Airport. During the approach phase, the two aircraft came within 0.6 nautical miles of each other horizontally and 200 feet vertically. Both flight crews received TCAS Resolution Advisories (RA) to avoid a collision. There were no injuries to the passengers or crew, and neither aircraft sustained damage.
The investigation
The investigation examined the air traffic control (ATC) procedures, the management of the Arrival Management (AMAN) system, and the coordination between different sectors of the Barcelona approach control. The investigation focused on the sequence of events leading to the conflict, specifically looking at the roles of the planning controllers and executive controllers in the T1W, T4W, and F2..'n sectors.
Findings
- The primary cause of the loss of separation was incorrect planning and execution of the approach sequence by the T1W sector and inadequate conflict resolution by the F24W sector.
- Inadequate coordination between the T1W and T4W sectors led to an unnecessary change in the established approach sequence.
- The T1W sector planner physically intervened in the positions of other controllers and performed inadequate verbal coordination.
- There was inadequate management of aircraft speeds, headings, and altitudes by the T1W sector.
- The executive controller in the final sector (F24W) lacked awareness regarding the flight levels of the involved aircraft and instructed the D-AGWD aircraft to descend to an altitude that was unavailable.
- The F24W executive controller was unaware of the loss of separation alerts and failed to manage the flight parameters effectively to prevent the conflict.